salt pan

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An undrained shallow depression in which water accumulates, evaporates, and deposits salt.
• noun A small lake of brackish water occupying such a depression.

from The Century Dictionary.

• noun A large shallow pan or vessel in which salt water or brine is evaporated in order to obtain salt.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A flat expanse of ground naturally covered with salt and other minerals; this is the accumulation of salts and minerals as water, unable to drain into the ground, evaporates.
• noun A man-made pond where salty water is evaporated to concentrate it during the making of salt.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a shallow basin in a desert region; contains salt and gypsum that was deposited by an evaporated salt lake